Process and apparatus for festooning fibrous strand

ABSTRACT

A METHOD AND APPARTUS FOR FESTOONING A PLURALITY OF PARALLEL FIBROUS STRANDS OVER SUPPORT MEANS PROVIDED AT OPOSITE ENDS OF AN ELONGATED HEATING CHAMBER AND, WHEN REQUIRED BY BREAKAGE OF ONE OR MORE OF STRANDS, FOR REPLACING BROKEN STRAND BY LIFTING THE REMAINING STRANDS FROM AT LEAST ONE OF SAID SUPPORT MEANS AND INTRODUCING ADDITIONAL FIBROUS STRAND IN PARALLEL, COPLANAR, RUNNING ALIGNMENT THEREWITH.

" Sept. 20, 1971 :KALLE'NBQRN EI'AL 3,606,116

PROCESS AND APPARATUS FOR FESTOONING FIBROUS STRAND 5 Sheets-Sheet 1 Filed March 5, 1970 Sept. 20, 1971 KALLENBQRN ET AL 3,606,116

- PROCESS AND APPARATUS FOR FESTOONING FIBROUS STRAND Filed March 3, 1970 5 Sheets-Sheet 2 INVENTOR6 Jail/Y mus/vice 660/905 3. ZUZME OE ATTORNEY,

p 20, 1971 J. KALLENBORN ET PROCESS AND APPARATUS FOR FESTOONING FIBROUS STRAND Filed March 5, 1970 5 Sheets-Sheet 3 INVENTORI' JOHN mull/MM 0R0! I. Z URflE/DE h ATTORNEYS p 20, 1971 J. KALLENBORN AL 3,506,116

PROCESS AND APPARATUS FOR FESTOONING FIBROUS STRAND Filed March 5, 1970 5 Sheets-Sheet 4 D D .l

D \D J INVENTORS JOHN KALLENFORN GEORGE B ZURHE/DE ATTORNEYS Sept. 20, 1971 J- KALLENBORN ET PROCESS AND APPARATUS FOR FESTOONING FIBROUS STRAND Filed March 5,

5 Sheets-Sheet 5 INVENTORS Jan/v AALLEMEOfiN 650/865 6 zap/mo:

MMKBTMQM/ ATTORNEYS United States Patent 3,606,116 PROCESS AND APPARATUS FOR FESTOONING FIBROUS STRAND John Kallenborn, Murrysville, and George B. Zurheide,

Upper St. Clair, Pa., assignors to PPG Industries, Inc.,

Pittsburgh, Pa.

Filed Mar. 3, 1970, Ser. No. 16,004 Int. Cl. B65l 17/00 US. Cl. 226-1 6 Claims ABSTRACT OF THE DISCLOSURE A method and apparatus for festooning a plurality of parallel fibrous strands over support means provided at opposite ends of an elongated heating chamber and, when required by breakage of one or more of the strands, for replacing broken strand by lifting the remaining strands from at least one of said support means and introducing additional fibrous strand in parallel, coplanar, running alignment therewith.

BACKGROUND OF THE INVENTION This invention relates to festooning fibrous strand in an elongated heating chamber and, more particularly, to restranding or refestooning fibrous strand through an elongated heating chamber while continuously moving a plurality of such strands along a common path relative thereto. Specifically, the present invention provides an improved process and apparatus for festooning elastomeric adhesive coated glass fibrous strands in a curing oven and, when required by breakage of one or more of the strands, for replacing broken strand by lifting the remaining strands from support means provided therefor and introducing additional elastomeric adhesive coated glass fibrous strand in parallel, coplanar, running alignment with the unbroken strands.

In copending application Ser. No. 605,814, filed Dec. 29, 1966, and assigned to the assignee of the present invention, there is disclosed the use of a novel process employing high frequency electrical heating, such as dielectric heating, to dry a plurality of coated glass fibrous strands that are wet or saturated with elastomeric dip. As is set forth more fully in that application, the use of dielectric drying permits subsequent processing of the coated glass fibrous strands over rolls, pulleys and the like without stripping off coating material and/ or depositing coating material on supporting and conveying elements. In particular, the above-mentioned application discloses that where it is desired or required to pass the coated glass fibrous strands through a curing oven sub sequent to drying, the dielectric drying permits faster production speeds for a given length of curing oven, the use of shorter curing ovens, and better process control than was the case with conventional drying and curing processes that do not utilize dielectric drying. Specifically, is was found that elastomeric adhesive coated strand can be processed at least five to six times faster through the curing oven when exposed first to dielectric drying than was possible when dielectric drying was not used.

While the foregoing disclosure of said copending application represents a significant advancement in processing elastomeric adhesive coated glass fibrous strand, problems arose in connection with the process and apparatus disclosed therein. Among these problems were those of initially festooning the curing oven with a multitude of coated strands to provide several redirected passes for the strands through the oven; providing a suitable support arrangement for the strands that remains substantially unaffected by continual exposure to the heated environment in the oven; preventing strand entanglement with the strand support means; and restranding or refestooning the oven in the event of strand breakage so that substantially uninterrupted processing of a full complement of strands can be maintained without shutdown.

In accordance with the present invention, the foregoing problems are resolved by providing a unique process and apparatus for readily and eificiently festooning and/or refestooning fibrous strand through an elongated heating chamber or oven. Moreover, pursuant to this invention there is provided a novel support arrangement for the fibrous strands which is particularly adapted for trouble free use and operation in connection with the contemplated festooning, conveying and/ or refestooning of the strands through the oven.

In particular, this invention contemplates a novel process and apparatus for substantially continuous, uninterrupted heat treatment of a multitude of coated strands which are arranged in generally parallel, coplanar, running alignment and which make several redirected passes through a heated oven. For the purpose of 'festooning and/or refestooning the coated strands, the invention teaches affixing the strand to a bar adapted to traverse a path approximating the desired strand path and deposit the strand on sheaves or pulleys providing support means in the oven for the festooned strand. Also, where the stranding bar must cross over running strand in order to introduce an additional strand into the festoon, the process and apparatus of the invention is such that the bar contemporaneously lifts the running strand from its pulley support means, introduces the additional fibrous strand in generally parallel, coplanar alignment with the running strand, and thereafter deposits the running strand and the additional strand on their respective pulley support means.

The present invention also teaches the use of strand support means in the oven comprising a plurality of axially aligned pulleys each having the peripheral rim portion of one side thereof nested in concentric interfitting relation with the peripheral rim portion of one side of its adjacent pulley. The pulleys are preferably provided with polytetrafluoroethylene bearings. As thus constructed and arranged, the strand support means has been found to be substantially unaffected by continual exposure to the heated environment in the oven. Also, the overlapping or interfitting arrangement of the pulleys has effectively precluded strand from getting between adjacent pulleys and breaking, as well as becoming entangled with and/ or jamming the pulleys or the pulley shaft.

The above and other objects, features and advantages of this invention will become more apparent when considered in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagrammatic representation of a typical process that may advantageously employ the teachings of the present invention;

FIG. 2 is a schematic perspective, partly in section, of the curing oven of FIG. 1 illustrating some of the details of the festooning process and apparatus of this invention;

FIG. 3 is a partial section of the curing oven of FIG. 1, where viewed from its right side in relation to strand take-oft occurring at the front of the oven, illustrating further details of the festooning process and apparatus of this invention;

FIGS. 4-6 are partial schematic perspectives of the lower intermediate strand support, when viewed from the left side of the curing oven, showing successive steps in the process of restranding or refestooning strand on this support;

FIG. 7 is a partial front elevation of the thread-up bar of this invention; 'and FIG. 8 is a partial front elevation of either of the upper strand supports in the curing oven showing typical details of the strand support structure of this invention and the relationship of the thread-up bar thereto as it passes over either of the mentioned strand supports.

Referring to FIG. 1, there is shown a creel .10 having mounted thereon a plurality of bobbins 12 containing glass fiber strand 14. Each of the glass fiber strands 14 is coated with a sizing material comprising a lubricant, binder and coupling agent, such as disclosed in U.S. Pat. No. 3,437,517, assigned to the assignee of the present invention. Other suitable size materials that contain suitable coupling agents may be found in US. patent applications Ser. No. 599,180, filed Dec. 5, 1966, and Ser. No. 601,341, filed Dec. 13, 1966, now abandoned. Furthermore, as is conventional, each of the glass fiber strands 14 has imparted therein a 0.5 turn per inch twist to provide strand integrity and resistance to fuzzing during initial handling or processing prior to being coated and impregnated with elastomeric material.

The strands 14 are combined in parallel relation and passed through ceramic guides 16 in tangential contact across motor-driven rotating rollers or dip applicators 18 to a motor-driven rotating wiper roller or pulley 20. The rollers or clip applicators 18 are partially suspended in an aqueous elastomeric dip or adhesive 22 contained within vessels or tanks 24. The dip applicators 18 are driven counter to the direction of travel of the strands 14 to improve the coating and impregnation thereof. The pickup of dip 22 by the applicators 18 and strands 14 is more than sufficient to coat and impregnate the strands with the desired final amount of elastomeric adhesive material 22. The wiper roller or pulley is driven counter to the direction of travel of the strands 14 and serves to further impregnate the strands while removing excess dip or adhesive material 22.

From the wiper roller or pulley 20, the coated, impregnated strands are passed vertically through a dielectric heater or drying oven 25. Dielectric heater 25 comprises a vertically arranged series of spaced parallel electrodes 26 electrically connected to a suitable power source (not shown) to produce an alternating high-frequency electrical field 27 between successive oppositely charged electrodes. Since the detailed construction and principle of operation of dielectric heaters does not, per se, form a part of the present invention, reference is made to US. Pat. No. 2,503,779 for typical details. For a complete understanding of the present invention, it will be sufiicient to point out that as strands 14 coated and impregnated with aqueous elastomeric dip 22 traverse across but not contacting the electrodes 26 and parallel to and through fields 27, the liquid component of the dip, which has a higher dielectric constant than the solid component, is electrically activated to produce a uniform heating action throughout dip material 22. For the purpose of the present invention, the rate and amount of electrical activation or dielectric heating is controlled to the extent of removing or volatilizing substantially all of the liquid component of the aqueous dip material while leaving the solid component substantially unaffected. The coated and impregnated strands 14 as they leave dielectric heater 25 are free of bubbles and sufliciently dry and free of tack for the purpose of further processing the strand over rolls, pulleys or the like without fear of stripping oif coating material and/or depositing coating material on supporting and conveying elements or the like.

After leaving dielectric heater 25, the coated strands pass upwardly and then traverse through an elongated heating chamber 28, such as a hot gas oven, to cure or react the solid components of the adhesive. With particular reference to FIGS. 1 to 3, vertical heating chamber or oven 28 is open at the bottom and is provided with suitable heat supply, air circulating and exhaust means (not shown). Mounted within heated oven 28 are three 4 transversely extending strand supports 30, disposed substantially as shown, and constructed and arranged to permit festooning a multiplicity of strands thereabout so that the strands are supported in parallel, coplanar, running alignment with each other as the strands make several redirected passes through the oven.

Strand supports 30 are shown schematically in FIGS. 1-6 and in detail FIG. 8. With reference to FIG. 8, each strand support 30 comprises a set of identical pulleys or sheaves 32 mounted on a common shaft with each pulley having the peripheral rim portion 34 of one side thereof nested in concentric interfitting relation with the peripheral rim portion 36 of one side of its adjacent pulley. The pulleys are preferably composed of cast aluminum and are fitted with polytetrafluoroethylene bearings 38 to provide for free rotation of each of the pulleys 32 about pulley shaft 49. Polytetrafluoroethylene bearings are selected because they are self-lubricating, relatively chemically inert and exhibit low thermal expansion as well as little change in other physical properties at temperatures normally present in the curing oven. As will be appreciated, the interfitting or overlapping arrangement of the pulleys is specifically designed to preclude strand from disengaging grooves 42 or otherwise getting between adjacent pulleys and breaking, as well as becoming entangled with and/or jamming pulleys 32 on their pulley shaft 40.

As shown in FIGS. 1-3, elongated heating chamber or oven 28 is preferably provided with at least three strand supports 30 or three sets of pulleys 32 in the oven for the purpose of festooning strands 14 thereabout to provide several redirected passes for the strands through the oven. Two of the strand supports 30 are located at the same approximate elevation, at or near the top of the oven, with their axes in spaced, parallel relation to each other so that one strand support resides near the rear of the oven and the other resides near the front of the oven, as viewed from the take-up winder 44. The third strand support, as shown, is located at the bottom of the oven in a position intermediate the top strand supports and with its axis parallel to the axes of the top strand supports. An additional strand support or pulley assembly 46 is supported below the lower front edge of the oven for the purpose of guiding or conveying the cured strand from the oven to take-up winder apparatus 44. As thus arranged, strand supports 30 and additional strand support 46 provide for four redirected passes of the strand through the oven.

Each pulley shaft 40 of the strand supports 30 is releasably coupled at its ends to opposed stub shafts 48 extending inwardly of the oven from both sides thereof. Mounted on each stub shaft, for free rotation thereabout on polytetrafluoroethylene bearings, are identical sprockets 50 of a diameter somewhat greater than the diameter of pulleys 32. The sprockets 50 are thus independent of the strand supports 30 so that each strand support, comprising a pulley set and pulley shaft, can be removed, cleaned, reworked and/or replaced, if necessary, without disturbing any of the sprockets. Additional, opposed sets of smaller sprockets 52, 54, 56 and 58, as shown in FIGS. 2 and 3, are mounted from front to rear below the lower extremities of the sides of oven 28 to provide a chain path there-along. Two continuous chains 60 engage the above-mentioned sprockets so that at each side of the oven a continuous chain path is provided from lowed rear sprocket 58 to upper rear sprocket 50, to lower intermediate sprocket 50, to upper front sprocket 50, to lower front sprocket 52, to lower intermediate sprockets 54 and 56 and then back to lower rear sprocket 58. As best shown in FIG .2, lower front sprockets 52 are joined together by a drive shaft suitably journaled in plates 62 extending below opposite sides of the oven. An extension of this drive shaft extends through one of the plates 62 and, by means of a pulley on the extended end, is belt driven by a reversible motor 64 so that both chains 60 may be driven simultaneously at the same speed. The set of sprockets 54 are suitably mounted and biased by a conventional arrangement (not shown) to provide slight tension in chains 60 and to take up any slack that may occur therein as a result of thermal expansion.

As illustrated in FIGS. 2-6 and best shown in FIGS. 7 and 8, a thread-up bar 66 is releasably attached at each end to horizontally aligned support lugs 68 (one of which is shown) which are aflixed to laterally opposed links of each of the chains 60. Thread-up bar 66 comprises an elongated cylindrical member provided with a longitudinally arranged series of spaced grooves that correspond in location and spacing with the grooves in the rims of pulleys 32. Thread-up bar 66 and sprockets 50 are suitably dimensioned such that as chains 60 convey the thread-up bar in an arcuate path around the strand supports 30, adequate clearance is provided between the thread-up bar and the strand supports.

For a thorough understanding of the invention, reference is now made to the method of operating the apparatus described above in connection with festooning and refestooning fibrous strand through oven 28. Initially, a plurality of fibrous strands which have been threaded from the creel 10, across rollers 18 and up through dielectric oven 22 are secured, as by tying their free ends, to successive grooves in thread-up bar 66. Motor 64 is then energized and thread-up bar 66 is conveyed by chains 60 in its predetermined path across upper rear, lower intermediate and upper front strand supports 30 to a final position below the lower front of the oven. As thread-up bar 66 passes across each strand support 30, each strand is deposited in the groove of a pulley. When thread-up bar 66 reaches its final position below the lower front of the oven, the strands are removed from the thread-up bar 66 and, while maintaining their preordained parallel alignment, are deposited in successive grooves in pulley assembly 46, from which they are drawn to take-up winder 44. Thread-up bar 66 is then released from lugs 68 and, by driving the motor in either direction, lugs 68 are returned to their initial position below the lower rear of the oven. Thread-up bar 66 is thereafter re-attached to lugs 68 for subsequent use should refestooning of broken strand become necessary.

In the event one or more strands should break while being drawn through the apparatus by take-up winder 44, the free strand end extending from the creel is affixed or tied to the thread-up bar 66 in the position it previously occupied relative to the running strand. Then, while the remaining strands are still running, the thread-up bar 66 is conveyed by the motor driven chains 60 through the oven 28 in the same manner as described above in connection with initially festooning the oven. However, with reference to FIGS. 4-6, when refestooning or restranding a broken strand in the specific oven embodiment shown, the thread-up bar 66 moves between the running strands and the lower or intermediate strand support 30 and contemporaneously lifts the running strands from the lower strand support, introduces the additional or replacement strand in generally parallel, coplanar alignment with the running strands and, thereafter, deposits the running strands and the replacement strand on the lower strand support. As will be understood, the alignment of the grooves in the thread-up bar 66 with the grooves in the pulleys of the lower strand support facilitates avoiding any lateral disalignment of the strands during the steps of picking up the running strands and redepositing these strands on their respective strand support pulleys. As with initial festooning, when the threadup bar 66 reaches a position below the lower front of oven 28, the replacement strand or strands are removed from the thread-up bar, guided into their respective pulley grooves in pulley assembly 46 and re-attached to the take-up winder. The thread-up bar 66 is then released from lugs 68, withdrawn laterally from the front of the oven, the lugs are driven to their initial position below the lower rear of the oven and the thread-up bar 66 is re-attached for use when later needed.

It will be apparent from the foregoing description of a preferred embodiment of this invention that the stranding or rethreading system disclosed herein does not require the strand supports 30 to be located in the oven 28. In particular, the strand supports 30 could be located outside the curing oven 28 without affecting the operation and/or performance of the disclosed stranding and rethreading system.

We claim:

1. Apparatus for lifting a plurality of parallel fibrous strands that are running over strand support means and through an elongated heating chamber, and for introducing additional fibrous strand in parallel, coplanar, running alignment therewith comprising a bar, means for afiixing said additional fibrous strand to said bar in desired lateral position relative to said running strands and means for moving said bar between said running strands and said strand support means to contemporaneously lift said running strands from said strand support means, introduce said additional fibrous strand in generally parallel, coplanar alignment with said running strands and, thereafter, deposit said running strands and said additional strand on said strand support means.

2. Apparatus according to claim 1 wherein said strand support means is located in said elongated heating chamber.

3. Apparatus according to claim 2 wherein said strand support means comprises a plurality of axially aligned pulleys with each pulley having the peripheral rim portion of one side thereof nested in concentric, interfitting relation with the peripheral rim portion of one side of its adjacent pulley.

4. Apparatus according to claim 3 wherein each pulley is mounted for free rotation about a pulley shaft on a polytetrafluoroethylene bearing.

5. Apparatus according to claim 1 wherein said strand support means is located outside of said elongated heating chamber.

6. A method for lifting a plurality of parallel fibrous strands that are running over strand support means and through an elongated heating chamber, and for introducing additional fibrous strand in parallel, coplanar, running alignment therewith which comprises affixing said additional fibrous strand to a bar in desired lateral position relative to said running strands and moving said bar between said running strands and said strand support. means to contemporaneously lift said running strands from said strand support means, introduce said additional fibrous strand in generally parallel, coplanar alignment with said running strands and, thereafter, deposit said running strands and said additional strand on said strand support means.

References Cited UNITED STATES PATENTS RICHARD A. SCHACHER, Primary Examiner US. Cl. X.R. 226-92, 104, 109 

